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Model-independent assessment of the late-time dark energy density evolution

Rayff de Souza1,2,*, Agripino Sousa-Neto1,†, Javier E. González3,‡, and Jailson Alcaniz1,§

  • *Contact author: rayffsouza@on.br
  • †Contact author: agripinoneto@on.br
  • ‡Contact author: javiergonzalezs@academico.ufs.br
  • §Contact author: alcaniz@on.br
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Phys. Rev. D 113, 103531 – Published 19 May, 2026

DOI: https://doi.org/10.1103/5zv5-yhwk

Abstract

Combined measurements of baryon acoustic oscillations (BAOs) from the Dark Energy Spectroscopic Survey (DESI), the cosmic microwave background (CMB), and type Ia supernovae (SNe Ia) have recently challenged the Λ cold dark matter (ΛCDM) paradigm, indicating potential evidence for a dynamical dark energy component. These results are usually obtained in the context of the dark energy equation-of-state (EOS) parametrizations, generally implying in phantom crossing at intermediate redshifts. However, a general mapping between these parametrizations that yields approximately the same background observables clouds the inference of the true nature of dark energy in the context of these parametric methods. In this work, we propose a model-independent reconstruction of the dark energy density, which is more directly constrained than its EOS, based on the Gaussian process (GP) regression method with the use of DESI Data Release 2 BAO and compressed CMB data along with the Pantheon+, Union3, and Dark Energy Survey Supernova Year-5 (DESY5) SNe Ia samples. In addition, we perform a statistical comparison between the energy densities of Λ, a nonphantom thawing quintessence-type dark energy, and the Chevallier-Polarski-Linder parametrization with the reconstructed function. We find that all models agree with the GP reconstruction at 95% confidence level, with the largest discrepancy coming from ΛCDM with DESY5 at low redshifts. Even in this case, our findings suggest that it may be premature to claim statistically significant evidence for evolving or phantom dark energy with current DESI and SNe Ia measurements.

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Phys. Rev. D 113, 103531– Published 19 May, 2026
  • Received 9 December 2025
  • Accepted 16 April 2026
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